They will be sentenced on June 6 with Judge Nicholas Hilliard QC, the Recorder of Greenwich, warning them: "This will attract significant custody. There is no doubt about that."

The murderous plan targeting the English Defence League (EDL) fell apart because the gathering in Dewsbury, West Yorkshire, finished earlier than expected. Police and security services had no intelligence about the planned attack on June 30 last year, although Uddin was under surveillance in relation to another terrorist plan.

Ahmed was also on bail for possession of terrorist documents at the time of the plot.

All of the men except Hasseen travelled to the rally armed with two shotguns, swords, knives, a nail bomb containing 458 pieces of shrapnel, and a partially assembled pipe bomb, ready to cause mass injuries and deaths. The nail bomb was an 18-inch (46cm) long rocket which was stuffed with shrapnel and was to be powered by explosives taken from at least two large fireworks.

Police estimated there could have been up to 750 EDL marchers at the Dewsbury event, but also dozens of officers and innocent passers-by. The fanatics' plan failed by chance, because they arrived at 4pm when the rally had dispersed by 2pm.

The planned atrocity was only uncovered because a traffic officer stopped Uddin and Khan on the M1 as they travelled home to Birmingham. Checks showed their Renault Laguna was uninsured, so the car was impounded. Two days later staff at the pound near Sheffield looked at the contents of the Renault and found the gang's arsenal.

There were also 10 copies of a hate-filled note addressed to the enemies of Islam, the Queen and Prime Minister David Cameron. It said: "This is a message to the enemies of Allah and his messenger. This is a message to the kafir (non-believer) female devil and self-proclaimed Queen Elizabeth and her accursed jubilee, fooling a nation of blind sheep to your self-proclaimed royalty and majesty."